Prior, it has been known that certain ester compounds of 3-Z-(1-propenyl)-2,2-dimethylcyclopropanecarboxylic acid exhibit an excellent insecticidal effect in GB-1304141A. Further, the method described in the Scheme A below is known as a typical method for producing the ester of 3-Z-(1-propenyl)-2,2-dimethylcyclopropanecarboxylic acid (J.C.S. 1970, 1076). ##STR2##
However, the above-mentioned method is not sufficient for industrially practical scale since it needs dangerous reagents, which are difficult to deal with in industry, such as alkali metal amides. Therefore, it is desired to develop an industrially advantageous method for producing 3-Z-(1-propenyl)-2,2-dimethylcyclopropanecarboxylic acid and its esters.